This depends on the level of support you need. Two members of staff might be fine for non-critical systems but it’s not enough to support anything that needs to be up 24/7. There’s not enough coverage and less than zero slack. If my alternative is to hire two people, I would rather spend the money with a company that is large enough to employ more people, in different timezones. But if most support can be handled by a larger body of existing staff and you only need specialists occasionally, then it might make sense.